The master thesis deals with the possibility of using dynamic damper in hydrodynamics. Specifically, the assessment of the impact of dynamic damper on the dynamic stability of the fluid system when the system exhibited unstable behaviour prior to damper installation due to self-excited vibration. In the thesis is presented the algorithm for the calculation of pressure and flow pulsations based on the transfer matrix method, the transition matrices for different damper designs variants are derived. Using the algorithm, the effect of a damper placed in a stable and unstable fluid system is solved. The output of this work is software for solution of pressure and flow pulsations in the system with serially arranged hydrodynamic elements created in the MATLAB program.

The thesis discusses the fiber Bragg gratings simulations, analysis and design. In the present time, there are several methods to simulate fiber gratings response based on the stated parameters that define their dimensions and material features. However, this work deals with a different issue, that is the synthesis of the input parameters for demanded spectral responses. The main aim of the work is to achieve a synthesis method that would help to discover parameters describing advanced grating structure, based on the required spectral reflectivity. The basic demand for the parameter synthesis is an achievement of the real values in terms of the consequent production of the suggested structure. The described synthesis method considers advanced fiber grating structure as a structure of several uniform grating sections. The input parameters are estimated in steps, using the well-known direct methods in order to obtain grating responses and feedback to establish the parameters changes. The principle methods involve establishment of initial input parameter values and necessary subsequent algorithm leading to optimize the required spectral response. The initial values are calculated by a simplified model based on the coupled theory equations that are handled for the periodic disturbances in cylindrical waveguide. The following optimization uses the multiple thin film stack and transfer matrix methods. The properties of grating structure spectral reflectivity are step by step calculated while using these direct methods. Input parameters are established in the next several steps. Establishment of input parameters is done subsequently, based on the demanded and calculated output spectral reflectivity properties. Optimizing process is limited by possibilities of the grating manufacture technology. It is possible to assemble arbitrary fiber grating structure taking in term the demanded spectral response. Nevertheless, the calculated input parameters are real for the following manufacture. This method could be used to design optical band stop filter, high-pass and low-pass filters or filters for special applications.

Acoustic absorbing liners are efficient and commonly used measures to reduce sound levels in many fields of application. The sound reducingperformance of the liners is dependent on the acoustic state, defined by e.g. the flow and sound field interacting with the liner. To enable liner optimization the impact of these factors on the liner performance must be predictable. Studies of the impact of these factors were performed with existing experimental, analytical and numerical methods at low Mach number flows and material used in truck engine compartments. The study showed significant impact of both flow and sound field onthe liner performance. The size of the impact of the flow depends on which of the existing methods and models that was used, implying theneed of complementary methods. A new numerical method to model the boundary layer effect was for this reason developed in this work. The method was shown to predict the impact of flow correctly compared to the Pridmore-Brown solution and the method was computationally efficient. The sound reducing performance of a liner exposed to complex sound field and grazing flow can be predicted using existing methods together with the new proposed method. Extra care has to be taken when bulk reacting liners are considered since additional complications compared to locally reacting surfaces occur in presence the of grazing flow. / <p>QC 20130916</p>

A theoretical study has been carried out on different methods available to analyze complex mufflers. Segmentation methods have been discussed in detail. The latest two port segmentation method has been discussed and employed for a few common muffler configurations, describing its implications and limitations. A new transfer matrix based method has been developed in view of the lacunae of the available approaches. This Integrated Transfer Matrix (ITM) method has been developed particularly to analyze complex mufflers. An Integrated transfer matrix relates the state variables across the entire cross-section of the muffler shell, as one moves along the axis of the muffler, and can be partitioned appropriately in order to relate the state variables of different tubes constituting the cross-section. The method presents a 1-D approach, using transfer matrices of simple acoustic elements which are available in the literature. Results from the present approach have been validated through comparisons with the available experimental and three dimensional FEM based results. The total pressure drop across perforated muffler elements has been measured experimentally and generalized expressions have been developed for the pressure loss across cross-flow expansion, cross-flow contraction elements, etc. These have then been used to derive empirical expressions for flow-acoustic resistance for use in the Integrated Transfer Matrix Method in order to predict the flow-acoustic performance of commercial mufflers. A flow resistance model has been developed to analytically determine the flow distribution and thereby pressure drop of mufflers. Generalized expressions for resistance across the perforated elements have been derived by means of flow experiments as mentioned above. The derived expressions have been implemented in a flow resistance network that has been developed to determine the pressure drop across any given complex muffler. The results have been validated with experimental data.

The validity of transfer matrix method (TMM) employed in a nonlinear gear cam system is studied in this thesis. The nonlinear dynamic responses of each part in the nonlinear system are estimated by applying the 4th-order Runge-Kutta method. A high speed gear cam drive automatic die cutter was analyzed in this study. A 25 horsepower AC induction motor is designed to drive the system. To complete the cutting work, a sequential process of the harmonic motion and the intermittent motion are generated by the elbow mechanism and the gear cam mechanism, respectively. A simplified branched multi-rotor system is modeled to approximate the motion of the system. The variation of the dynamic parameters of the system in a loading cycle is estimated under a branched torsional system. The Holzer¡¦s transfer matrix method is used to study the variation of the system parameters during the intermittent movement. Moreover, the effect of time-varied speed introduced from the torque variation of the induction motor and gear cam mechanism on the nonlinear dynamic response of the system has also been investigated. To explore the dynamic effect of different cam designs, three different cam motion curves and seven operating rates have been analyzed in this work. The residual vibration of the last sprocket has also been discussed. Numerical results indicate that the proposed model is available to simulate the dynamic responses of a nonlinear gear cam drive system.

Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2017-03-20T12:36:39Z No. of bitstreams: 1 TeseDAN.pdf: 8462805 bytes, checksum: 612f3289bd6eedee49e627d6f99f7762 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-04-20T13:36:31Z (GMT) No. of bitstreams: 1 TeseDAN.pdf: 8462805 bytes, checksum: 612f3289bd6eedee49e627d6f99f7762 (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-04-20T13:36:43Z (GMT) No. of bitstreams: 1 TeseDAN.pdf: 8462805 bytes, checksum: 612f3289bd6eedee49e627d6f99f7762 (MD5) / Made available in DSpace on 2017-04-20T13:54:43Z (GMT). No. of bitstreams: 1 TeseDAN.pdf: 8462805 bytes, checksum: 612f3289bd6eedee49e627d6f99f7762 (MD5) Previous issue date: 2016-10-31 / Não recebi financiamento / In this Thesis we propose to describe the thermodynamical properties of dimer chains in a one-dimensional lattice rstly considering q-states of chain orientation in the lattice and secondly by a three states model where the chain orientation is associated with a energy " > 0 or " = 0. For this reason we describe our system by a microcanonical ensemble to get the canonical partition function and through this function obtain the Helmholtz free energy, the entropy, internal energy and pressure. We solved also the problem by adopting the grand canonical ensemble using the transfer matrix method and we get in the thermodynamical limit the equivalence between both ensembles. However the analysis of the thermodynamic properties for systems with nite size is quite relevant since for these nite systems can be found a inequivalence of ensembles. Thereby we performed a detailed study of the Statistical Mechanics for nite particles systems verifying the equivalence o ensembles. / O presente trabalho tem por finalidade descrever as propriedades termodinâmicas de cadeias de dímeros em uma rede unidimensional, inicialmente considerando q-estados de orientações das cadeias na rede, e posteriormente um modelo de 3 estados, onde orientação da cadeia está associada a uma energia " > 0 ou " = 0. Para isso, consideramos o problema de um ponto de vista combinatório, no ensemble microcanônico, de maneira a obter sua função de partição canônica e através dela encontrarmos as grandezas termodinâmicas de interesse, tais como a energia livre de Helmholtz, entropia, energia interna, pressão, por exemplo. Posteriormente, resolvemos o problema no ensemble grande canôncio usando a técnica de matriz de transferência, obtendo assim, no limite termodinâmico a equivalência entre os ensembles. Entretanto, têm-se tornado cada vez mais importante e frequente, o estudo termodinâmico de sistemas “pequenos", onde nestes casos pode haver a inequivalência entre as grandezas físicas obtidas nos ensembles. Desse modo, realizamos um estudo detalhado do que acontece ao aplicarmos ferramentas da mecânica estatística a sistemas com poucas partículas, verificando se os diferentes ensembles estatísticos estudados neste trabalho ainda levam aos mesmos resultados.

No description available.

This Master thesis desires the design of methodology for calculating shaft deflection and critical speed of electric machines. There are two methods used. The first one is transfer matrix method, which is represented by a simple programme for shaft creation and calculating needed results built in the Matlab software. The second one is finite element method, which is presented in the Ansys Workbench software.

<p>U ovoj disertaciji, izvršena su teorijska i eksperimentalna istraživanja dinamičkog onašanja jezgra visokih zgrada. Model je zasnovan na Vlasovoj teoriji tankozidnih nosača, kao i na metodi prenosnih matrica. Jezgro se tretira kao tankozidni nosač otvorenog poprečnog preseka, koji je na dnu uklješten u temeljnu ploču, dok je na vrhu&nbsp; slobodan.&nbsp; Duž&nbsp; ose&nbsp; smicanja,&nbsp; jezgro&nbsp; je&nbsp; podeljeno&nbsp; na&nbsp; čvorove&nbsp; u&nbsp; nivoima spratova&nbsp; u&nbsp; kojima&nbsp; su&nbsp; redukovane&nbsp; mase.&nbsp; Poseban&nbsp; naglasak&nbsp; je&nbsp; stavljen&nbsp; na&nbsp; analizu uticaja poprečnih greda, međuspratnih ploča, kao i načinu oslanjanja međuspratnih ploča po spoljašnjoj konturi na dinamičke karakteristike jezgra. Razvijeni&nbsp; numerički&nbsp; postupak&nbsp; je&nbsp; primenjen&nbsp; na&nbsp; armiranobetonskom&nbsp; jezgru petnaestospratne zgrade, koja je analizirana ranijeu radovima mnogih autora. U tu svrhu korišćen je računarski program TWBEIG, napisan primenom Visual Fortran programskog jezika. Analize su urađene i MKE, a dobijeni rezultati su upoređeni. Vrednosti sopstvenih frekvencija pokazuju dobro slaganje.<br />Ovaj rad daje detalje i o eksperimentalnoj studiji&nbsp; u kojoj se primenjuje pleksiglas model u cilju pružanja eksperimentalnih podataka zaproveru tačnosti i pouzdanosti numeričkih&nbsp; rezultata.&nbsp; Dobijeni&nbsp; rezultati&nbsp; su&nbsp; takođe&nbsp; upoređeni&nbsp; sa&nbsp; rezultatima dobijenim TWBEIG računarskim programom, kao i MKE.<br />Predstavljeni&nbsp; numerički&nbsp; metod&nbsp; nudi&nbsp; solidnu&nbsp; osnovu&nbsp; za&nbsp; formiranje&nbsp; jednostavnog modela&nbsp; proračuna,&nbsp; a&nbsp; ipak&nbsp; obezbeđuje&nbsp; odgovarajući&nbsp; nivo&nbsp; preciznosti.&nbsp; Predloženi postupak&nbsp; može&nbsp; biti&nbsp; korišćen&nbsp; i&nbsp; u&nbsp; fazi&nbsp; prethodne&nbsp; analize&nbsp; zgrade,&nbsp; kao&nbsp; i&nbsp; u&nbsp; fazi konačnog projektovanja.</p> / <p>In this dissertation, a theoretical and experimental study of the dynamic behaviour<br />of&nbsp; the&nbsp; tall&nbsp; buildings&nbsp; core&nbsp; was&nbsp; carried&nbsp; out.&nbsp; The&nbsp; model&nbsp; is&nbsp; based&nbsp; on&nbsp; the&nbsp; Vlasov&#39;s<br />theory of thin-walled beams and the transfer matrixmethod. The core is treated as<br />a thin&nbsp; wall-walled, open cross section cantilever beam. Along the shear axis the<br />core&nbsp; is&nbsp; divided&nbsp; into&nbsp; nodes,&nbsp; in&nbsp; the&nbsp; level&nbsp; of&nbsp; the&nbsp; floors,&nbsp; in&nbsp; which&nbsp; the&nbsp; masses&nbsp; are<br />reduced.&nbsp; Special&nbsp; emphasis&nbsp; was&nbsp; given&nbsp; to&nbsp; the&nbsp; analysis of&nbsp; the&nbsp; influence,&nbsp; of&nbsp; lintel<br />beams,&nbsp; floor&nbsp; slabs,&nbsp; as&nbsp; well&nbsp; as&nbsp; the&nbsp; type&nbsp; of&nbsp; restraints&nbsp; along&nbsp; the&nbsp; outer&nbsp; edge&nbsp; of&nbsp; the<br />floor slabs, on the dynamic characteristics of the core.<br />The&nbsp; developed&nbsp; numerical&nbsp; procedure&nbsp; was&nbsp; applied&nbsp; to&nbsp; the&nbsp; fifteen-storey&nbsp; reinforced<br />concrete core tall building, analyzed previously inthe papers of many authors. For<br />this&nbsp; purpose,&nbsp; the&nbsp; computer&nbsp; program&nbsp; TWBEIG&nbsp; was&nbsp; used, written&nbsp; using&nbsp; Visual<br />Fortran programming language. The analyses were also performed with FEM and<br />subsequently the results were compared. The values&nbsp; of natural frequencies show<br />significant agreement. This&nbsp; paper&nbsp; presents&nbsp; details&nbsp; about&nbsp; the&nbsp; experimental&nbsp; study&nbsp; which&nbsp; applies&nbsp; the plexiglas model in order to provide experimental data to verify the accuracy and reliability of the numerical results. The results are also compared with the results obtained with the TWBEIG computer program, as well&nbsp; as with FEM. The values of frequencies show reasonable agreement.<br />The proposed numerical&nbsp; method offers a solid base&nbsp; for the creation of a&nbsp; simple<br />calculation model, yet provides the appropriate level of precision. It can be either<br />used for preliminary analysis or for the final design.</p>

No description available.